The use of wind power as a source of energy, especially windmills, has a long history tracing for hundreds of years. But these windmills were designed for fulfilling specific needs on specific sites and could not provide electrical energy for large grid of electrical power because they had too small scale and could not meet necessary standard for electrical power because of constant change of their speed of rotation and absence of means for controlling this speed. Propellers, used in most power plants, that we can see, for example, in California, cannot provide us with a solution. Even theoretically they cannot use all the energy of areas swept by propellers because they move in plane perpendicular to the direction of the wind. The surface of propeller should be curved to face the wind with proper angle, and it is difficult to build a wide propeller blade twisted at the hub. Also, we cannot build too long blades because it faces too big distractive centrifugal forces in cross section of their twisted blades near the hub. Since the energy of the wind corresponds to the surface of its cross section, narrow blade faces narrow strip of the wind and receives a small portion of energy of the wind that passes by. At the same time, big amount of small size plants consumes too much areas of the land. They don""t have good aesthetic view, are bad for bird population and difficult for maintenance, especially in case of stormy weather or snow.
Wind power plant, proposed by Heidelberg, Fed. Rep. of Germany, U.S. Pat. No.; 5,299,913, date of patent Apr. 5, 1994, includes a plurality of upright rotor blades, which could be more longer lasting than propeller blades. This plant also comprises energy conversion means for converting rotary motion into electrical energy. But this plant cannot have more than six narrow blades of special shape (see column 4, 10), so the output of energy, which depends of surface of the blades, disposed to the direction of the wind, cannot be big. This plant also doesn""t have any control of the rotational speed, any safety measures and means for maintenance, especially, as it proposes to be located at the sea, and will be broken after the first storm, when the wind can be too erratic and very strong.
International publication number WO 00/45050, International publication date 3 Aug. 2000, applicant and inventor Israelsson Alf, Stockholm (SE), describes a wind power plant, which includes many narrow parallel arranged wind absorbing blades, suggesting that they will move with medium speed (see page 3a) on carriages. These carriages are connected one after the other in an oblong and closed track in a direction perpendicular to the direction of the wind. Each blade has its own electrical correcting unit that should correct the pitch angle regulation. But it is not clear, what and when will send signals to these units. And how the author of the invention knows, that the carriages with the blades will move with medium speed along the track. Sooner, the proposed conveyor with blades will move erratically, and sometimes stop completely, depending of the changing speed of the wind or direction of the wind. The friction between the wheels of the carriages and the tracks can be too high and will be changing with every change of the wind because part of the force of the wind, impacting on the blades, pushes the wheels perpendicular to tracks. And every change of the angle of the blades also will change the vertical force onto the wheels and the force of friction between the wheels and the tracks.
Erratic movement of the generators cannot produce standard electric power. In this invention author also did not mention which means will orient the plant toward the wind. Because of oblong structure of this plant, it will always try to turn it in the direction of the wind on its rotational base while it needs to be placed perpendicular to wind in order to work.
United States Patent for Dec. 5, 2000, U.S. Pat. No. 6,157,088, inventor Horst Bendix, Leipzig, Germany, shows a wind energy system for utilizing of a decommissioned power station or industrial chimney as a tower for a wind converter with high electrical output and propeller type turbines with horizontal axis of rotation of the rotor. FIG. 8, FIG. 9 and FIG. 10 show different arrangements of several converters on one tower with height of the 300 meters.
But this energy system does not have any rate control and does not have any means for preventing synchronous speed of the rotors. The system also uses propeller type rotors with narrow blades and cannot utilize all the energy of the area swept by these propellers. It does not have any prevention against storm, snow, can harm the bird population, does not have any safety measures for maintenance and overhaul.
United States Patent for March 1919, U.S. Pat. No. 1,298,247, inventor John Muller, shows a windmill, containing a wind wheel, a windshield, and a tail vane. This windmill does not have means for controlling the wheel speed. The shield should cover near 180 degrees of wheel surface and is too big for easy operating.
United States Patent for Oct. 9. 1928, U.S. Pat. No. 1,687,181, inventor Thomas B. Prease, shows a wind motor, comprising a supportive frame, a vertical shaft, a rotor, rotating on this shaft, having a plurality of disks, secured to this shaft, blades disposed between the disks and rigidly secured to the disks.
This windmill does not have any rate control. A shield is covering 180 degrees of the surface of the rotor and it will cause eddying of the air in the narrow passage between the blades and the shield despite the openings in the shield: if the openings are too small, they will provide a little help; if the openings are big, the shield will not be a shield.
The blades are secured to disks but have curved surfaces in horizontal and vertical directions and too complicated, heavy and expensive to be implemented on a large scale. A rotor having blades of such bended shape can rotate under impact of the wind even without shield, and we can see small turbines working as fans on the roofs of different buildings, having similar shape of blades.
U.S. Pat. No. 2,252,523, for Windmill, inventor Milton Plotkin, patented Aug. 12, 1941, describes a structure, comprising a frameworks, in which is rotatable mounted a revolving shield, partially enclosing a wing-equipped rotor, exposed at one side thereof to the force of the wind; the shield is being provided with fins, which cooperate to ensure the proper automatic positioning of the shield, relative to the direction of the wind.
The shield is slightly less than 180 degrees of a circumferential length and present a vertical leading and trailing edges. The size of the shield is too big but it cannot cover from the snow or very strong wind more than 180 degrees of the surface of the rotor from the left side of axis of rotation, if the wind will change the directions too quickly. At the same time, the air, exiting the blades, will eddy between the rotor and the trailing edge and between rotor and shield from back-side of the rotor, decreasing the efficiency of the windmill. The inventor suggested to make the blades curved and bowed to diminish the eddies, but it would make the blades more complicated and the eddies still are present when the air will be pushed by the blades in a narrow passage between the blades and the shield from the half of the back side of the rotor.
Two fins, fixed to said shield, are forming pockets of air, one between trailing edge and the wall of the shield, the other for the flow of the air, exiting the blades from both sides of the second fin. It also creates additional eddies for the air, exiting the rotor and for the wind striking the fins from left and right sides, what will cause instability for the position of the shield and for the speed of the rotor. This windmill also does not have any means for rate control for the rotor.
U.S. Pat. No. 4,134,708, Jan. 16, 1979, Brauser et al. This patent describes a wind driven electric power plant comprising a rotor, a shield and a fin, mounted on a vertical, central shaft, a shield and a fin adjustable interconnected via a cog and gear track arrangement. Constant rotor rotation is achieved by masking the rotor by the shield and hydraulic rotation rate control system.
This plant cannot provide necessary safety measures in case of storm, when wind changes directions too quickly and its speed is too high. More than half of the blades will remain open to the wind and the material off the blades will be damaged. To maintain the constant rotor rotation rate it is necessary to constantly move the large shield, which is covering half of cylindrical surface of the rotor, imposing too much strain on cog 304 and gear teeth 286 (see FIGS. 4 and 5). It is too long way to go from gears to points 232, 254 on upper level, 254 to lower level 254 and rotate the flange 238. Since the shield should cover half of the surface of the rotor, the air will eddy near the back cutting edge of the shield. The canvas, used as material for the blades, can not stand too long and requires constant change, as we can see with the flags, exposed to the of wind for a too long time. The power outlet in this plant, as well as in many other previous inventions, is made with traditional transmission means to transmit the power from rotor to speed increaser and generator and do not use the idea of taking off the power with linear motion generator. This plant does not use computer for controlling its operation. In general, the design of this plant is too complicated for using on a large scale. It cannot be used if we will place one turbine above another because the fin is located above the rotor. It cannot be used with horizontal axis of rotation of the rotor.
U.S. Pat. No. 4,093,398, Jun. 6, 1978, Inventor Denver W. Miller describes a wind driven power mechanism, having a sail-type vanes, connected between two endless carriers, moving over upper arcuate run, while lower ends of the vanes are connected to rotatable idlers.
This mechanism does not have any rate control; the sails are subjects for quick wear and tear. The base of the housing can be driven around vertical axis by a motor, connected with pinion gear engaged with a ring gear, but this mechanism does not have any positional system for controlling this motor and finding direction of the wind. That mechanism has additional mechanical links to generator or pump and does not have direct outlet for generating electrical energy.
U.S. Pat. No. 4,930,985. Date of patent Jun. 5, 1990. Inventor Ferdinand Klute, Germany, describes a wind power plant, having wind sails moving along the length of passage structure under the force of the wind one after another in the direction of the wind. But the first sail, that faces the wind, will receive most of the energy of the wind. There is no wind behind it like behind a wall. All other sails will be located in the lee side of first sail, especially in a tunnel (see FIG. 8), so that the energy of the wind will be utilized only from the surface of one blade, all other blades along the chains are not working and senseless, and the force of the wind will be not enough even to move all this conveyors with blades, having big forces of friction along the tracks. We can easy imagine such a long conveyor with blades that even hurricane will not have enough power to move it, although the author suggests (page 11, 20) to protect the plant in case of a hurricane by turning the plant through 90 deg. It""s useless also because hurricane change the direction of the wind too quickly. If we will remove al this chains with blades and leave only two turbines 95 with surface of one blade of each of turbines equal to half of the surface of cross section of the tunnel 90, we will utilize the same energy of the wind, that suggest to utilize inventor F. Klute. Approximately similar solution with new design of wind power plant will be presented below in my proposed invention.
In the preview of the prior Art we can see mostly patents issued in the United States, but many authors of these patents live in different counties, representing their inventions in the U.S. The same could be said about many other patents in this branch of Art not cited in this preview.
In the conclusion of the preview of Prior Art we can say that until now there is no satisfactory solution for a wind power plant, which can operate as a unit comprising a plurality of rotors with wide blades under one roof, utilizing higher speed of the wind on higher elevation. There is no such a plant with computer-controlled speed of rotation of these rotors. There is no such a plant that has wind tail that can orient the plant toward general direction of the wind and, at the same time, accelerates the speed of the wind, directed to the turbines. There are only a few plants that are using direct conversion of wind energy into electrical energy, but they have completely different design of the plant. There are a few power plants, which have a plurality of rotors, but they also have completely different design, using narrow propeller type blades or locating rotors one behind another, so that the wind after impacting on the first rotor loses its energy and cannot rotate the second rotor. The known plants, that have a plurality of rotors, do not have means for preventing synchronous speed of rotation of these rotors and can fall apart.
The present invention contemplates a wind driven power plant for producing electrical energy on a big scale in which a plurality of turbines is collected in one housing, rotating around vertical axis on a strong base. The housing is having a lower platform, supportive towers and a roof, forming a rectangular air concourse, adapted for receiving flow of a wind from front side and exiting the wind from back side with general direction of the wind perpendicular to front side. Wind tail is attached to back side of the housing for positioning the housing toward direction of the wind and utilizing the impact of the wind onto outer surfaces of vertical walls, outstretched back from back side of the housing, while inner vertical walls provide tunnel suction inside the wind tail. Each of the turbines faces the wind from the front side of the housing, utilizing all the energy of the wind, and has its own system of wind tunnels, accelerating this wind. Each of turbines is having a rotor, equipped with wide blades. Front deflector, stationary attached to the housing, is deflecting the wind from 90 deg. of front side of the rotor, located above horizontal axis of rotation of the rotor, while leaving opened to the wind the remaining part, located below this axis of rotation. A governor, made in a shape of a 90 degrees arc surface and controlled by computer, changeably covers part or all of the remaining part of the front side of the rotor. Computer is constantly monitoring the speed of rotation of all of the rotors, keeping it constant despite of changes in the speed of the wind or changing it, or stopping the work of part of turbines or stopping the work of all of the turbines and covering surfaces of turbines in case of heavy snow, strong wind or change in demand. Computer also changes the speed of turbines in case of synchronous speed of two or more of them and thus maintaining constant speed of rotation. Electricity is produced by rotation of the system of permanent or electrical magnets, located from both sides of the rotors relative to coils, located on the housing with a small air gap between magnets and coils.
Rotors are equipped with wide blades, what allow to rotate the rotors even with a light wind and to produce a powerful torque. Positioning a plurality of turbines one above another allows to save occupied area of land and utilizes higher speed of wind on higher elevations.
An object of this invention is to provide a wind power plant for generating electrical energy on a big scale, comprising a plurality of turbines, collected under one roof, so that we will not occupy large areas of land, at the same time, increasing the efficiency of turbines by locating them on higher elevations, one above another and using the higher speed of the wind on higher elevations.
Another object of this invention is to the simplify the design and efficiency of the rotors by using wide blades made of thin sheet metal or another rigid, strong and durable material, like plastic.
Another object of this invention is to provide a torque for rotation of the rotors by covering the front side from one side of the axis of rotation by deflectors.
Another object of this invention is to maintain constant speed of rotation of the rotors despite changes in the speed of the wind by using computer controlled and easy operated governors for changeably covering from the wind evaluated part of remaining front side of the rotors, not covered by deflectors.
Another object of this invention is to make these governors smaller and easier operated than known in Prior Art.
Another object of this invention is to provide computerized monitoring of the speed of rotation of the rotors, changing its speed, completely stopping some of the turbines or all of them.
Another object of this invention is to provide computerized controlled difference in the speed of rotation of the rotors to avoid synchronous speed.
Another object of this invention is to provide means for safety during the storm, heavy snow and for maintenance by covering the working surfaces of turbines with deflectors and governors.
Another object of this invention is to provide the housing a possibility of positioning toward direction of the wind by adding wind tail to the back side of the housing and using inner surfaces of this tunnels as means for creating tunnel suction for the flow of the air, passing through the turbines.
Another object of the invention is to provide an outlet for electrical power through converting wind energy into electrical energy directly inside the turbines, without additional mechanical links. For this mutter, rotating parts of the generators are mounted to both sides of the rotors while stationary parts are mounted to the housing with air gaps between rotating and stationary parts and conductor systems positioned inside the housing.
Another object of this invention is to provide means for maintenance and overhaul by installing cranes under the roof of the housing and elevators with stops for every level of the plant.
Another object of this invention is to provide environment friendly plant with muffled noise of the working turbines behind the walls of the housing, deflectors and governors and not harming the bird population with opened blades by covering the entrances and the exits for the air with bird protective nets.
Another object of this invention is to create a wind plant with pleasant aesthetic view by making the plant looking like a skyscraper and covering the towers and wind tail with panels.
Other objects and advantages of the invention will become apparent from a consideration of the drawings and description.